U.S. Senate Republicans were struggling to pass President Donald Trump's sweeping tax-cut and spending bill early on Tuesday, amid deep divisions within the party about its expected $3.3 trillion hit to the nation's debt pile.

Senate Republicans can afford to lose no more than three of their own votes on the bill, but two already are opposed and others remained undecided.

The Senate is slogging through a tense overnight session that has dragged into Tuesday, with Republican leaders buying time as they search for ways to secure support for President Donald Trump's big bill of tax breaks and spending cuts while fending off proposed amendments, mostly from Democrats trying to defeat the package.